I realize that I’ve said it many times before, but it bears repeating. Homeopathy is the perfect quackery. The reason that homeopathy is so perfect as a form of quackery is because it is quite literally nothing. On second thought, I suppose that it’s not exactly nothing. It is, after all, water or whatever other diluent that homeopaths use (usually ethanol). However, thanks to some basic laws of physics and chemistry and a little thing known as Avogadro’s number, any homeopathic dilution greater than 12C (twelve serial 100-fold dilutions) is incredibly unlikely to contain even a single molecule of starting compound. That unlikeliness reaches truly astonishing levels as we reach the common homeopathic dilution of 30C, which is the equivalent of a 1060-fold dilution. Given that that little thing known as Avogadro’s number, which describes how many molecules of a compound are in a mole, is only approximately 6 x 1023, a 30C dilution is on the order of 1036– to 1037-fold higher than Avogadro’s number. Even assuming that a homeopath started with a mole of remedy before diluting (unlikely, given the high molecular weight of most of the organic compounds that can serve as homeopathic remedies), the odds that a single molecule could remain behind after the serial dilution and succussion process is infinitesimal. Appropriately enough, the “law” in homeopathy that states that diluting a remedy will make it stronger is the law of infinitesimals.

It is also the reason that homeopathy is nothing.

Homeopaths have known these facts for many decades. Anyone who is any sort of a scientist or has an understanding of science, when confronted with these simple, well-established physical laws, might—just might—start to rethink his belief in something that is so utterly implausible from a scientific standpoint. Indeed, homeopathy is about as close to impossible as anything I can imagine, because for it to “work” multiple well-established laws of physics and chemistry would have to be not just wrong, but spectacularly wrong. Yet, as Richard Dawkins famously put it, undeterred, homeopaths bravely paddle up the river of pseudoscience and invent explanations to “explain” how homeopathy could work, the most famous of which is the so-called “memory of water,” in which the water in the homeopathic remedy remembers all the good bits meant to heal but, as Tim Minchin so famously put it, somehow forgets all the poo that’s been in it. Homeopathy is truly magical thinking, which is why I love to use it as an illustrative example of quackery. Not only is it magical thinking, but because it is nothing but water, it’s a very useful educational example for placebo effects and the general types of fallacious arguments quacks and pseudoscientists make. Apparently it’s time for another one.(more…)